I am so sick of the MC solves racism/slavery in a horrifically racist/pro-slavery society. It seems to only exist to make the MC seems like a paragon of virtue, and to remind the readers how moral they are for agreeing that racism is bad. It's pathetic pandering and a horribly cheap way to establish characters. Even worse, it makes sure the formerly oppressed person worships the MC, not for actually saving them, but for being a nicer slave owner. It's okay to make this person a slave/servant because they'll treat them right!